Ingredients

For the Sandwich:
4 slices of thick white bread
4 slices of ham
1 cup grated Gruyère or Emmental cheese
1 tablespoon Dijon mustard

For the Béchamel Sauce:
2 tablespoons butter
2 tablespoons all-purpose flour
1 cup whole milk
A pinch of nutmeg
Salt and pepper to taste

For Topping:
1/4 cup grated Parmesan cheese

Directions

In a small saucepan, melt the butter over medium heat. Add the flour and whisk constantly for about 1 minute until it forms a smooth paste. Gradually whisk in the milk, continuing to whisk until the sauce thickens and comes to a gentle boil. Season with salt, pepper, and nutmeg. Remove from heat and set aside.

Preheat the oven to 400°F (200°C). Spread Dijon mustard on one side of each bread slice. Place a slice of ham on two slices of bread, top with half of the grated Gruyère or Emmental cheese, and close the sandwiches with the remaining bread slices, mustard side down.

Spread a thin layer of béchamel sauce on top of each sandwich, then sprinkle with the remaining Gruyère or Emmental cheese and Parmesan cheese.

Place the sandwiches on a baking sheet and bake in the preheated oven for 10-15 minutes, or until the cheese is melted and bubbly and the bread is golden and crispy. For an extra crispy top, broil the sandwiches for the last minute.

Serve hot with a simple salad or soup on the side. Enjoy!